Kindelberger moved the company's operations from Dundalk, Maryland to Los Angeles, California, which allowed flying year-round, and decided to focus on training aircraft, on the theory that it would be easier than trying to compete with established companies on larger projects. Its first planes were the GA-15 observation plane and the GA-16 trainer, followed by the O-47 and BT-9, also called the GA-16.[1]

The BC-1 of 1937 was North American's first combat aircraft; it was based on the GA-16.[1] In 1940, like other manufacturers, North American started gearing up for war, opening factories in Columbus, Ohio, Dallas, Texas, and Kansas City, Kansas.[1] North American ranked eleventh among United States corporations in the value of wartime production contracts.[3]

B-25 Mitchell bomber production line at the North American Aviation plant, Inglewood, California, October 1942. The plane's outer wings have yet to be added, which enables the two side-by-side assembly lines to be closer together. The outer wings will be attached outdoors, in the "sunshine" assembly line.[4]

North American's follow-on to the BT-9 was the T-6 Texan trainer, of which 17,000 were built, making it the most widely used trainer ever. The twin-engine B-25 Mitchell bomber achieved fame in the Doolittle Raid and was used in all combat theaters of operation. The P-51 Mustang was initially produced for Britain as an alternative to the Curtiss P-40 Warhawk, which North American had declined to produce under licence.[5][6] The derivative A-36 Apache was developed as a ground attack aircraft and dive bomber. A suggestion by the RAF that North American switch the P-51's powerplant from its original Allison engine to the Rolls-Royce Merlin engine may have been one of the most significant events in WWII aviation, as it transformed the P-51 into what many consider to be the best American fighter of the war.[1][7][8][9]

Post-war, North American's employment dropped from a high of 91,000 to 5,000 in 1946. On V-J Day, North American had orders from the U.S. government for 8,000 aircraft. A few months later, that had dropped to 24.[1]

Some 6,656 F-86s were produced in the United States, the most postwar military aircraft in the West, as well as another 2,500 elsewhere. To accommodate its Sabre production, North American opened facilities in a former Curtiss-Wright plant in Columbus, Ohio. It also moved into a former Consolidated-Vultee Aircraft plant at Downey, California, and in 1948, built a new plant at Downey. By the end of 1952, North American sales topped $315 million. Employment at the Columbus plant grew from 1,600 in 1950 to 18,000 in 1952.[1]

The cancellation of the F-107 and F-108 programs in the late 1950s, as well as the cancellation of the Navaho intercontinental cruise missile program, was a blow to North American from which it never fully recovered.

Atomics International was a division of North American Aviation which began as the Atomic Energy Research Department at the Downey plant in 1948. In 1955, the department was renamed Atomics International and engaged principally in the early development of nuclear technology and nuclear reactors for both commercial and government applications. Atomics International was responsible for a number of accomplishments relating to nuclear energy: design, construction and operation of the first nuclear reactor in California (a small aqueous homogeneous reactor located at the NAA Downey plant),[10] the first nuclear reactor to produce power for a commercial power grid in the United States (the Sodium Reactor Experiment located at the Santa Susana Field Laboratory)[11] and the first nuclear reactor launched into outer space by the United States (the SNAP-10A).[12] As overall interest in nuclear power declined, Atomics International transitioned to non-nuclear energy-related projects such as coal gasification and gradually ceased designing and testing nuclear reactors. Atomics International was eventually merged with the Rocketdyne division in 1978.[13]

Autonetics began in 1945 at North American's Technical Research Laboratory, a small unit in the Los Angeles Division's engineering department based in Downey, California. The evolution of the Navaho missile program resulted in the establishment of Autonetics as a separate division of North American Aviation in 1955, first located in Downey, later moving to Anaheim, California in 1963. The division was involved in the development of guidance systems for the Minuteman ballistic missile system.

The fatal Apollo 1 fire in January 1967 was partly blamed on the company. In March, it merged with Rockwell-Standard, and the merged company became known as North American Rockwell.[14] Within two years the new company was studying concepts for the Space Shuttle, and won the orbiter contract in 1972.[15] In 1973, the company changed its name again to Rockwell International and named its aircraft division North American Aircraft Operations.[16]

Rockwell International's defense and space divisions (including the North American Aviation divisions Autonetics and Rocketdyne) were sold to Boeing in December 1996. Initially called Boeing North American, these groups were integrated with Boeing's Defense division. Rocketdyne was eventually sold by Boeing to UTC Pratt & Whitney in 2005. UTC later sold Rocketdyne to Aerojet (GenCorp) in 2013.